10_87.cpp

C++程序设计技能百练随书配套光盘的源码

#include<iostream.h>
struct element
{  //定义节点结构
	int val;  //数据元素域
	element *next;  //链指针域
};
class list
{  //list类定义
	element *elems;  //elems为当前标识指针
public:
	list(){elems=0;}
	~list();  //析构函数
	virtual bool insert(int val);  //虚函数
	virtual bool deletes(int val);  //虚函数
	bool contain(int val);
	virtual void print();
};
class set:public list
{
	int card;
public:
	set(){card=0;};
	bool insert(int val);
	bool deletes(int val);	
	void print();
};

list::~list()
{
	element *tmp=elems;
	for(element *elem=elems;elem!=NULL;)
	{  //循环释放各元素所占的内存
		tmp=elem;
		elem=elem->next;
		delete tmp;
	}
}
bool list::insert(int val)
{  //插入元素函数
	element *elem=new element;  //分配内存
	if(elem!=NULL)
	{  //将新元素插入到当前标识指针elems处
		elem->val=val;
		elem->next=elems;
		elems=elem;
		return true;
	}
	else return false;
}
bool list::deletes(int val)
{  //删除元素函数
	if (elems==NULL)   //如链表为空返回false
		return false;
	element *tmp=elems;
	if(elems->val==val)
	{
		elems=elems->next;
		delete tmp;
		return true;
	}
	else
		for(element *elem=elems;elem->next!=NULL;elem=elem->next)
			if(elem->next->val==val)
			{
				tmp=elem->next;
				elem->next=tmp->next;
				delete tmp;
				return true;
			}
	return false;
}
bool list::contain(int val)
{  //判断元素val在链表中是否存在
	if(elems==NULL)
		return false;
	if (elems->val==val)
		return true;
	else
		for(element *elem=elems;elem->next!=NULL;elem=elem->next)
			if(elem->next->val==val)
			return true;
			return false;
}
void list::print()
{  //输出链表的各元素
	cout<<"调用基类的print()函数!"<<endl;
    cout<<"链表元素为：";
	if(elems==NULL) 
		return;
	for(element *elem=elems;elem!=NULL;elem=elem->next)
		cout<<elem->val<<" ";
	cout<<endl;
}
bool set::insert(int val)
{
	if(!contain(val) && list::insert(val))
	{
		++card;
		return true;
	}
	return false;
}
bool set::deletes(int val)
{
	if(list::deletes(val))
	{
		--card;
		return true;
	}
	return false;
}
void set::print()
{
	cout<<"调用派生类的print()函数!"<<endl;
	cout<<"集合元素为：";
	list::print();
	cout<<"集合元素个数为："<<card;
	cout<<endl;
}
void main()
{
	list *p,list1;
	set set1;
	p=&list1;
	p->insert(12);
	p->insert(34);
	p->insert(56);
	p->insert(78);
	p->insert(90);
	p->print();
	p->deletes(56);
	p->deletes(40);
	p->print();
	cout<<endl;
	p=&set1;
	p->insert(123);
	p->insert(234);
	p->insert(345);
	p->insert(123);
	p->print();
	p->deletes(123);
	p->deletes(456);
	p->print();
}